1. Field of the Invention
The present invention relates to a vehicle periphery monitoring system, and more particularly to a vehicle periphery monitoring system having an obstacle detecting unit for detecting the presence of an obstacle in the periphery of a vehicle and a controller for controlling an indicating unit to indicate the presence of an obstacle when the presence of such an obstacle is detected by the obstacle detecting unit.
2. Description of the Related Art
Heretofore, there have been known various systems for detecting an obstacle that is present in the periphery of a vehicle and indicating the detected obstacle to the driver of the vehicle. One known system employs sonic waves to detect an obstacle as disclosed in Japanese laid-open patent publication No. 2002-59798, and another conventional system detects an obstacle based on a contrast difference in a captured image as disclosed in Japanese laid-open patent publication No. H09-287915.
The former known system, which employs sonic waves to detect an obstacle, needs to keep a certain detection distance in which to detect obstacles in order to provide a certain detection range. However, since sonic waves that are radiated into the detection range are vertically spread, if the detection distance is equal to or greater than a predetermined distance, the system tends to also detect undangerous obstacles on the ground, such as pebbles and wheel blocks, and indicate those detected undangerous obstacles to the driver of the vehicle. Therefore, the system is liable to keep the driver excessively on full alert while in operation, i.e., to fail to give the driver an adequate sense of safety. The latter known system, which detects an obstacle based on a contrast difference in a captured image, requires a CPU having a high processing capability due to the need for processing the entire area of the captured image.